As explained in commit 03d2d5fc003f ("board: sifive: unmatched: set
fdtfile with unquoted variable.") using the syntax of
'fdtfile=CONFIG_DEFAULT_FDT_FILE' in the plain text environment files
will lead to extraneous and problematic "s in the output. This is fixed
by using fdtfile=DEFAULT_FDT_FILE which was introduced recently.

Acked-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Tom Rini <trini@konsulko.com>

Add documentation for the PHYTEC phyCORE-AM68x/TDA4x (J721S2 family) SoM.

Signed-off-by: Dominik Haller <d.haller@phytec.de>
Reviewed-by: Wadim Egorov <w.egorov@phytec.de>

Add support for the PHYTEC phyCORE-AM68x/TDA4x (J721S2 family) SoM.

Supported features:
- 4GB LPDDR4 RAM
- eMMC
- SD-Card
- Ethernet
- OSPI
- AVS
- debug UART

Signed-off-by: Dominik Haller <d.haller@phytec.de>
Reviewed-by: Wadim Egorov <w.egorov@phytec.de>